九寨沟7.0级地震的地震断裂及震源破裂的构造动力学机理研究  

STUDY ON SEISMIC FAULT AND SOURCE RUPTURE TECTONIC DYNAMIC MECHANISM OF JIUZHAIGOU M_S7.0 EARTHQUAKE

作　　者：李渝生[1] 黄超[1] 易树健 伍纯昊 

机构地区：[1]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都610059 [2]中国科学院成都山地灾害与环境研究所,成都610041 [3]中国科学院大学,北京100049

出　　处：《工程地质学报》2017年第4期1141-1150,共10页Journal of Engineering Geology

基　　金：国家自然科学基金创新研究群体科学基金(41521002);中国科学院重点实验室开放基金"断裂带内动力作用与表生灾变效应的能量耦合研究"(KLMHESP-17-06)资助

摘　　要：本文针对九寨沟7.0级地震的发震构造及震源破裂的构造动力学问题,从地质调查、测试与震源构造动力学理论分析相结合的角度阐明:此次地震发生在处于高法向应力左旋剪切受力状态的岷山隆起带北端与西秦岭地槽褶皱带之南缘文县—玛沁断裂相交汇部位;沿"九寨天堂"—震中—五花海以及上四寨村—中查—比芒一线发育的两条具有构造破裂特征的NW向地裂缝带,是"隐伏状"地震断裂错动造成的地表同震破裂,前者是本次地震的控震构造,后者是NW向断层的次级同震复活及扩展;此次地震的震源断层错动过程受NW331°走向的陡倾角(∠87°)断层节面控制的走滑型剪切破裂,断裂两端的剪切破裂表现出持续扩展趋势;震源构造动力学过程实质上是地壳深部沿NW方向左旋剪断"凸出体";地震断裂带两端破裂扩展的持续发展,将导致地壳"凸出体"逐步剪断贯通。The seismic fault and source rupture tectonic dynamics mechanism of Jiuzhaigou M s 7 . 0 Earthquake were studied in this paper based on the combination of geological investigation, test and source tectonic dynamic theoretical analysis. This earthquake occurred at the intersection of the northern margin of the Minshan uplift belt and the south of Wenxian-Maqin fault in the south margin of the West Qinling trough, where is under sinistral shear stress with high law stress. There are two tectonic ruptures with NW trending fissure zone along the line of “Jiuzhaigou Paradise”-epicenter-Wuhuahai and Shangsizhai Village-Zhongcha-Bimang, which is ground coseismic rupture caused by uhidden, earthquake fault, former is the structure controlling this earthquake, the later is the sub-coseismic resurrection and extension of the NW-trending fault; the displacement of source fault in this earthquake is strike-slip shear fracture dominated by deep angle fault with strike NW 331°and dip angle ∠87°, and the aftershock activity is controlled by two NW-trending faults, the shear fracture at both ends of the fault showed continuous expansion trends. T he source tectonic dynamic mechanism is actually sinistral cutting＂ protrusion” along NW in the deep of crust. The continuous expansion of rupture at both ends of seismic fault will produce the gradual breakthrough of the crustal ＂ protrusion＂.

关 键 词：九寨沟 地震 断裂 构造动力学 

分 类 号：P642.27[天文地球—工程地质学]